Radio apparatus



Jan. 1, 1929. 1,697,512

L. R. PAUST RADIO APPARATUS Filed Feb, 17, 1927.

Patented Jan. 1, 1929.

nAnIo arranarns.

Application filed February 17, 1927. Serial No. 168,857.

This invention relates to radio apparatus.

It frequently happens in radio reception that certain disturbing waves of almost the same frequen'c areeither just above or just below that o the received wave. Under these conditions, with the usual type oifreceiving sets, it is a practical impossibility to prevent disturbance as the waves of ap--' proximately the same length as the wave received are also impressedupon the set and cause considerable annoyance.

This invention is designed to overcome the defects noted above and objects of this invention are to provide a radio apparatus for eliminating unwanted signals, and to provide such an apparatus which is wholly automatic in its action and tunes'out the undesired signalsrb'oth immediately above and immediately below the range in which the set is working- Further objects are to provide adevice having the characteristics enumerated above which is of relatively simple construction, which is easy-to produce, and which is very easy to operate. I

An embodiment Figure 1 is a schematic view showing th arrangement of the apparatus I i Figure 2 is diagrammatic view showing the mechanicalconnecting of the rotors of the several condensers. 7

Referring to Figurel, it will be seen that the antenna 1 is connected through a series of coils 2, 8, and 4 to the ground 5. The coils 2, 3, and4 each consist of a few turns of relatively heavy wire. Associated with the coils, and electromagnetically coupled thereto are a series of coils 6, 7 and 8 which consist of a relatively large number of turns of wire and which are connected to variable condensers 9, 10, and 11. The condenser 9 has the lowest capacity for any given setting; the condenser 10 the next higher capacity; and the condenser 11,1the highest capacity; all of them being approxi ately,

in the same range but diflering slig tly in value. The coils 6, 7 and 8 may be identical in construction as may also the coils 2, 3, and 4.- If desired, a different arrangement may be had by varying the number of.

turns in the coils 6, 7, and 8 and makingthe condensers 9, 10, and 11 of the same capacity at any given setting. A

The purpose of this construction is to provide three tuned circuits. 7 The one shown permits a single tuning ofthe' entire appawill automatically tune the other circuits to of the invention is shown 1n the accompanylng drawings in wh1c h:-

or just below that received by the set, and

4 "1 7, 2 PATENT. OFFICEQI in the central portion of Figure-1 is tuned to the desired wave length to be received by the set, the one above to a wave length shorter than that desired, and the one below' to a wave length greater than the one desired. 7 i Any suitable connection may extend from the condenser 10 or coil 7 to the receiving set. For example,'opp0site sides of the condenser 10 are connected to the grid 12 and one side of the filament 13 of the first yacuum tube 1 1 of the set.

It 'is tobe noted that one side of each bf thev condensers 9, 10, and 11, is electricall 7 connected. For example, the rotors 9'., 10 and 11 of the condensers 9', 10, and 11 may be mechanically and electrically connected bythe rotor shaft 15 (see Figure 2). This ratus so that the set may be deed in the usual manner in which these receiving sets are cfistomarily tuned. The tuning of the central circuit to the desired wave length 8 wave lengths just above and'just belowthatreceived by the set. r

' 'It is to be distinctly understood that other forms than the one=shown in the drawing may be employed. For example, the two resonant wave trap circuits may be placed. directly in theantenna circuit, and the tun ing circuit leading to the set may be electromagneticallyor otherwise connected to the antenna circuit. If the wave trap circuits are placed in the antenna circuit while the tuning circuit is electromagnetically coupled to the wave trap circuits, 1t will be found desirable to avoid electric'al connection between the condenser of the tuned receiving circuit" and the condensers of the wave trap circuit although the condenser of the wave trap circuits may have an electrical connection between their rotors.

The essential idea in this invention, itwill be seen is to provide wave trap circuits tuned simultaneously with the receiving circuit leading. to the set with the wave trap circuits tuned just above and just below thefwave length of the.receiving circuit. I

Thisinvention, therefore, is designed to suppress the undesired signals or'disturbing waves which havea wave length Just above it will be seen that means have been provided for simultaneously tuning both the suppressing circuits and the receiving circuit.

It will be seen further that the apparatus is very simple to construct and very easy to ad ust, and requires no thought on the part of the operator, but is automatically tuned when the receiving circuit is tuned to the desired wave.

It is apparent that if the condensers are desired electricall separate and distinct, their rotors could e connected by a bakclite shaft, and this structure would not depart from the scope of this invention.-

Although the invention has been described in considerable detail, such description is intended as illustrative rather than limiting as the invention may be variously embodied and as the scope of such inventionis to' be determined as claimed.

I claim; 1

three primaries connected in series, three secondaries'associated with said primaries, three tuning circuits connected to said secondaries and each including a tuning condenser, said condenscrs having a common shaft electrically connecting one side of each of the condensers, one of said tuning circuits having leads extending from opposite sides of the secondary to an electron discharge device, the other two tuning circuits having electrical constant-s determining their period of oscillation, and said periods being respectively higher and lower than the period of oscillation of said first mentioned tuning circuit. l

In testimony that I claim the foregoing I have'hereunto set my hand at Joliet, in

the county of Will and Stateof Illinois. In a radio receiving system, the ,combination of an antenna circuit including LAWRENCE R. PAUST. 

